"""Read and write Jupyter notebooks as text files"""

from .jupytext import readf, writef, writes, reads
from .formats import NOTEBOOK_EXTENSIONS, guess_format, get_format_implementation
from .version import __version__

try:
    from .contentsmanager import TextFileContentsManager
except ImportError as err:
    class TextFileContentsManager:
        """A class that raises the previous ImportError"""
        err = err

        def __init__(self, parent=None, log=None):  # noqa
            raise self.err


def load_jupyter_server_extension(app):  # pragma: no cover
    """Use Jupytext's contents manager"""
    if isinstance(app.contents_manager_class, TextFileContentsManager):
        app.log.info("[Jupytext Server Extension] NotebookApp.contents_manager_class is "
                     "(a subclass of) jupytext.TextFileContentsManager already - OK")
        return

    # The server extension call is too late!
    # The contents manager was set at NotebookApp.init_configurables

    # Let's change the contents manager class
    app.log.info('[Jupytext Server Extension] Changing NotebookApp.contents_manager_class '
                 'from {} to jupytext.TextFileContentsManager'.format(app.contents_manager_class.__name__))
    app.contents_manager_class = TextFileContentsManager

    try:
        # And rerun selected init steps from https://github.com/jupyter/notebook/blob/
        # 132f27306522b32fa667a6b208034cb7a04025c9/notebook/notebookapp.py#L1634-L1638

        # app.init_configurables()
        app.contents_manager = app.contents_manager_class(parent=app, log=app.log)
        app.session_manager.contents_manager = app.contents_manager

        # app.init_components()
        # app.init_webapp()
        app.web_app.settings['contents_manager'] = app.contents_manager

        # app.init_terminals()
        # app.init_signal()

    except Exception:
        app.log.error("""[Jupytext Server Extension] An error occured. Please deactivate the server extension with
    jupyter serverextension disable jupytext
and configure the contents manager manually by adding
    c.NotebookApp.contents_manager_class = "jupytext.TextFileContentsManager"
to your .jupyter/jupyter_notebook_config.py file.
""")
        raise


def _jupyter_nbextension_paths():  # pragma: no cover
    """Allows commands like
     jupyter nbextension install --py jupytext
     jupyter nbextension enable --py jupytext
     jupyter labextension install jupyterlab-jupytext"""
    return [dict(
        section="notebook",
        # the path is relative to the `jupytext` directory
        src="nbextension",
        # directory in the `nbextension/` namespace
        dest="jupytext",
        # _also_ in the `nbextension/` namespace
        require="jupytext/index")]


__all__ = ['readf', 'writef', 'writes', 'reads',
           'NOTEBOOK_EXTENSIONS', 'guess_format', 'get_format_implementation',
           'TextFileContentsManager', '__version__']
